Transgenic expression of Rho-EGFP. (A) Constructs used to generate transgenic frogs. The color-coded regions above correspond to the colors of the amino acids below (PAGFP is shown). E/PAGFP was placed on the C terminus of Xenopus rod opsin with a single amino acid linker (H). The eight C-terminal amino acids of bovine rhodopsin were added to the C terminus of the GFP sequences. (B) Images of dissociated rod outer segments showing variable expression patterns of Rho-GFP. (Left) Trans-illumination images acquired with 700-nm wavelength illumination. (Right) Epifluorescence images acquired with 488-nm excitation. (C) Fluorescence of the outer segments shown in B averaged radially and plotted against axial distance. The top panel in C shows the fluorescence distribution of the dimmer cell in the top panels of B.